A bit out of date

[Mark Lee]

Hello, very new to Erlang so please forgive the ignorance at this stage.
I've been looking through some online examples of code and have seen
things like ++ and ||

Where might I find the documentation for these? I've got the Concurrent
Programming in Erlang book which appears to be somewhat behind with
respect to these language features (unless I've missed them).

Thankyou,

Mark